STAR CITY, RUSSIA
— Anatoly Solovyov, who blasts off on Tuesday as commander of the rescue mission to the crippled Mir space station, is an ace rocket pilot and one of Russia's most highly skilled cosmonauts.

But on this voyage, it will be his talents as a do-it-yourself handyman that will be most in demand.

The first order of business for Commander Solovyov and Flight Engineer Pavel Vinogradov will be to rewire Mir, which has been limping around its orbit on less than half power since a collision June 25. And once they've got the solar batteries reconnected, they will be using the same sort of epoxy resin that you might use to fix the body of a beat-up car to patch holes in the Spektr laboratory module and restore its pressure.

To mission control's relief, Solovyov is a practically minded man who is good with his hands. "He has golden fingers," grins Col. Viktor Ren, head of weightlessness training at Star City, Russia's cosmonaut-training compound northeast of Moscow.

"Those suits are a tremendous encumbrance," says Jerry Miller, a NASA expert in spacewalks who has been monitoring Solovyov's training program here. "It is very challenging to do dextrous work."

Underwater repair

That much was clear from watching cosmonauts practice repairing a replica of Spektr submerged in a giant pool recently. Every move was agonizingly slow and awkward.

It took the crew four hours just to rehearse installing handrails on the module's shell, so that they would have something to hang on to while looking for holes.

"The large gloves that are pressurized against the vacuum [of space] are very stiff," explains Mr. Miller. "Your hands have to fight the stiffness of the suit, you have to constantly correct for drift when you are outside to control your position. You are drifting, your equipment is drifting, and you are maneuvering a multi-hundred pound suit amongst your equipment just to get at the work site.

"Extra-vehicular activity is as much an art as it is a science," he says.

The first spacewalk, planned for Aug. 20, will actually take place inside the depressurized Spektr module, where conditions are more like outer space. The most urgent job there is to reconnect the windmill-like solar batteries - disconnected after Mir collided with a cargo vessel last month - to the rest of the craft.

At present, according to Yuri Koptev, head of the Russian space agency, "the power supply system can only guarantee life support and not a large-scale and coordinated program of scientific and technical experiments" that Mir is meant to host.

Electricity shortages pose longer-term problems to the space station itself, points out Miller, since the air conditioning has been turned down to save power, and humidity levels are high. This is more than simply uncomfortable for the cosmonauts aboard; in zero-gravity, condensation droplets can float into the electronics.

"You want to get the power re-established as soon as possible," Miller says. "Once that is done, you can do the exterior work at leisure."

Pass the magnifying glass

That work, though, is not going to be easy. The location of the holes, created when the Progress cargo ship bumped and scraped its way along the Spektr module during a bungled docking maneuver, is not known. Although scratches are bound to be visible, "the biggest problem may be to find the holes, or cracks," says Colonel Ren.

Russian experts have calculated that the holes - probably two of them - total about half a square inch. But they could be much smaller. Insulation panels will have to be removed from the outside to find the damage, and one solar battery, bashed beyond repair in the collision, will be dismantled, according to Ren.

Solovyov and Vinogradov will have the equipment to perform six space walks of up to 9-1/2 hours each. They will take some of their tools with them, and more equipment will go up in the US shuttle Atlantis on Sept. 28, when it delivers astronaut David Wolf.

Even if all the repairs go as planned, some experiments on Spektr have been ruined beyond recovery by the loss of pressure.

And even if Mir's constant problems are rarely life threatening, the space station's advanced age is becoming a hindrance to the science it is meant to support.

"The problem is not safety," says Leopold Eyharts, a French astronaut who has postponed his stay on Mir until January, when the space station will be in better shape for scientific experiments.

"The main problem is that there is such a big workload of repairs, and the station's technical situation has an impact on the scientific program," he says.

Repair work is nothing new to Russian cosmonauts. In 1983, the crew of Salyut 6 had to remove the shell of their spaceship while it was in orbit in order to repair its pneumatic-hydraulic system, and Mir crews have been fixing things on board the space station for years.

This is not surprising, says Yuri Semyonov, head of Energiya, the Moscow-based company that makes many of the components for Russian spacecraft, including Mir. When Mir was launched 11 years ago, its life span was set at three years.

But "we provided for the possibility of repair and maintenance work, and there is no instrument inside the station that cannot be replaced in flight," he says.

Good on-the-job training

Indeed, says Mr. Semyonov, looking on the bright side, "the fact that these problems have arisen gives us an enormous opportunity to store up experience for future work" on the Alpha international space station, due to begin construction next year.

"What tools are needed, how the crew should behave: This is immense experience that cannot be acquired on the ground," he says.